Search results for " Glycoproteins"
showing 10 items of 329 documents
Serologic Response to Cell Wall Mannoproteins and Proteins of Candida albicans
1998
SUMMARY The cell wall of Candida albicans not only is the structure in which many biological functions essential for the fungal cells reside but also is a significant source of candidal antigens. The major cell wall components that elicit a response from the host immune system are proteins and glycoproteins, the latter being predominantly mannoproteins. Both the carbohydrate and protein moieties are able to trigger immune responses. Although cell-mediated immunity is often considered to be the most important line of defense against candidiasis, cell wall protein and glycoprotein components also elicit a potent humoral response from the host that may include some protective antibodies. Prot…
Diagnosis of systemic candidiasis by enzyme immunoassay detection of specific antibodies to mycelial phase cell wall and cytoplasmic candidal antigens
1993
Diagnosis of systemic Candida infections was attempted by the use of an enzyme-linked immunosorbent assay (EIA) to detect IgG antibodies towards cell wall-bound and cytoplasmic candidal antigens. Cell wall antigens were sequentially solubilized by treatment of germinated blastoconidia of Candida albicans (ATCC 26555 strain) with beta-mercaptoethanol (beta ME extract) and digestion with Zymolyase 20T, a beta-glucanase preparation (Zymolyase extract). Protoplasts obtained after treatment with Zymolyase were osmotically lysed (cytoplasmic antigens). Sera were obtained from patients with systemic (n = 28) and superficial (n = 46) candidiasis. Control sera were obtained from normal healthy indiv…
Identification of residues in the putative 5th helical region of human interleukin-6, important for activation of the IL-6 signal transducer, gp130
1996
AbstractWe have previously shown that L58 in the putative 5th helical region of human interleukin-6 (IL-6) is important for activation of the IL-6 signal transducer gp130 [de Hon et al. (1995) FEBS Lett. 369, 187–191]. To further explore the importance of individual residues in this region for gp130 activation we have now combined Ala substitutions of residues E52, S53, S54, K55, E56, L58 and E60 with other substitutions in IL-6, known to affect gp130 activation (Q160E and T163P). The combination mutant protein with L58A completely lost the capacity to induce the proliferation of XG-1 myeloma cells, and could effectively antagonize wild type IL-6 activity on these cells. Moreover, the data …
Signaling pathways of the TREM-1- and TLR4-mediated neutrophil oxidative burst.
2008
The triggering receptor expressed on myeloid cells 1 (TREM-1) is involved in the innate inflammatory response to microbial infections. Activation and expression of TREM-1 by polymorphonuclear neutrophils (PMN) occurs in concert with Toll-like receptors (TLR) such as TLR4 for bacterial lipopolysaccharide. However, it is currently unclear how this is mediated on a molecular level. Using pharmacological inhibitors and Western blot analysis we demonstrate that phosphatidyl inositide 3-kinase, phospholipase C and the mitogen-activated kinase p38MAPK are essential for the TREM-1- and TLR4-induced oxidative burst of human PMN. The activation of protein kinase B and extracellular signal-related kin…
Membrane insertion and topology of the TRanslocating chain-Associating Membrane protein (TRAM)
2011
The translocating chain-associating membrane protein (TRAM) is a glycoprotein involved in the translocation of secreted proteins into the endoplasmic reticulum (ER) lumen and in the insertion of integral membrane proteins into the lipid bilayer. As a major step toward elucidating the structure of the functional ER translocation/insertion machinery, we have characterized the membrane integration mechanism and the transmembrane topology of TRAM using two approaches: photocross-linking and truncated C-terminal reporter tag fusions. Our data indicate that TRAM is recognized by the signal recognition particle and translocon components, and suggest a membrane topology with eight transmembrane seg…
Interleukin-6 and Soluble Interleukin-6 Receptor: Direct Stimulation of gp130 and Hematopoiesis
1998
T HE INTERLEUKIN-6 (IL-6) family of cytokines acts via receptor complexes that contain at least one subunit of the signal transducing protein gp130.[1][1] The family comprises IL-6, IL-11, ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), leukemia inhibitory factor (LIF), and oncostatin M
Leucine-58 in the putative 5th helical region of human interleukin (IL)-6 is important for activation of the IL-6 signal transducer, gp130
1995
A model of the tertiary structure of human IL-6, derived from the crystal-structure of granulocyte-colony stimulating factor, reveals a 5th helical region in the loop between the first and second alpha-helix. To investigate the importance of this region for biological activity of IL-6, residues Glu-52, Ser-53, Ser-54, Lys-55, Glu-56, Leu-58, and Glu-60 were individually replaced by alanine. IL-6.Leu-58Ala displayed a 5-fold reduced biological activity on the IL-6 responsive human cell lines XG-1 and A375. This reduction in bioactivity was shown to be due to a decreased capacity of the mutant protein to trigger IL-6 receptor-alpha-chain-dependent binding to the IL-6 signal transducer, gp130.
The family of the IL-6-type cytokines: specificity and promiscuity of the receptor complexes.
1997
The cytokines IL-6, LIF, CNTF, OSM, IL-11, and CT-1 have been grouped into the family of IL-6-type cytokines, since they all require gp130 for signal transduction. Interestingly, gp130 binds directly to OSM, whereas complex formation with the other cytokines depends on additional receptor subunits. Only limited structural information on these cytokines and their receptors is available. X-ray structures have been solved for the cytokines LIF and CNTF, whose up-up-down-down four-helix bundle is common to all of these cytokines, and for the receptors of hGH and prolactin, which contain two domains with a fibronectin III-like fold. Since cocrystallization and x-ray analysis of the up to four di…
Redistribution of aquaporin-4 in human glioblastoma correlates with loss of agrin immunoreactivity from brain capillary basal laminae
2003
Vasogenic edema is one of the most serious clinical problems in brain tumors and tightly connected to water shifts between the different fluid compartments in the brain. Aquaporin water channels have been recognized to have an important impact on the development of edematous swelling in the brain. Astrocytes, which are believed to induce or at least maintain the blood-brain barrier in the brain capillary endothelial cells, express the aquaporin isoform AQP4. Normally, AQP4 is highly concentrated in the glial membrane where astrocytes contact mesenchymal space, such as perivascular or brain superficial regions. Parenchymal membranes do not show any immunocytochemical AQP4-specific signal. We…
The membrane distal half of gp130 is responsible for the formation of a ternary complex with IL-6 and the IL-6 receptor
1995
AbstractGp130 is the signal transducing subunit of the interleukin-6 receptor. Signaling is initiated by the complex formation of gp130 with IL-6 bound to the IL-6 receptor (IL-6R). We have subdivided the extracellular domain of gp130 in two parts and expressed the mutant proteins as soluble IgG fusion proteins in COS-7 cells. By studying the formation of the ternary complex we show that the membrane distal half of gp130 which contains a cytokine receptor domain is responsible for the interaction with the IL-6/IL-6R complex. Interestingly this is the same region which is believed to be involved in specific recognition of the related cytokines LIF, OM, and probably also of CNTF and IL-11.